Patent documents 1 and 2 propose operation apparatuses using tilt operations for input to electronic apparatuses. For instance, a tilt operation is performed in a predetermined direction with a predetermined tilt center functioning as a supporting point. Of this tilt operation, displacement in the predetermined direction is detected, as an input, by a detector such as a sensor or switch.
In these operation apparatuses, one detector is assigned to one tilt direction; in specific, each of four detectors is provided to detect one of four tilt directions. This causes disadvantage that a large number of detectors are required although the number of tilt directions is relatively limited. This does not allow additional increase in the number of tilt directions or continuous detection in all the directions. This does not propose detection for another operation other than the tilt operation.                Patent document 1: JP-2003-220893 A        Patent document 2: JP-2002-202850 A        